The principal objective of the proposed research is to achieve an understanding of the pathway of biosynthesis, mechanism of secretion and function of carcinoembryonic antigen in tumor tissues. The multienzyme systems in tumors which regulate the composition, rate of synthesis and secretion of tumor antigens will be examined in structural studies and in studies of isolated cells, and cell-free particulate multienzyme systems. Methods have been developed in this laboratory for the isolation of CEA from liver metastases of colon, pancreas, and breast adenocarcinomas in high yield. Our present efforts are being directed towards completely characterizing these purified glycoproteins. It is not yet certain what changes occur during neoplastic transformation which lead to the synthesis of CEA. In order to compare the structure of CEA with glycoproteins present in the normal cell it is necessary to have highly purified preparations of CEA. The isolation and characterization of homogenous preparations of the antigen are also required before studies on its biosynthesis in tumor tissue can be initiated. The structure of the carbohydrate moiety of the antigen must be determined before specific glycosyl acceptors for glycosyltransferases present in tumor tissue can be prepared. We then plan to examine the enyzyme systems which are involved in the synthesis and secretion of these glycoproteins in adenocarcinomas.